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By Daniel Fischer Every page present in Europe & the U.S.!
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| An experimental German companion. Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
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Cygnus X-3: Waiting for the next big bangOne of the brightest x-ray sources in the Milky Way seems about to erupt in a dazzling flare: Cyg X-3, a black hole or a neutron star that's accreting matter from a companion. Because of the deep gravity well, a huge amount of energy can be released in x- and gamma-rays. It's also a very bright radio source that undergoes massive flares from time to time. During an intense flare in 1997, a VLBA radio map showed one-sided radio jet, about 50 milliarcseconds long. Two days later it extended to 120 mas and then it disappeared: This likely makes Cyg X-3 a galactic blazar, a jet source where we were looking straight down the jet, the first example of a blazar in our own galaxy. Before such a phenomenon was only known in Active Galactic Nuclei of other galaxies, very far away.The next opportunity to study Cygnus X-3 during a bright flare may be just around the corner. Just before a major flare, the radio and hard X-ray emission from Cygnus X-3 drops very low and stays there for days or weeks - as if something is building up before the explosion. On February 18 the radio emission from Cygnus X-3 dropped to very low levels and it's stayed there since. The hard X-ray (20-100 keV) emission which BATSE on the CGRO satellite usually detects from this source also vanished in late January: This is probably the precursor of some major activity - and several satellites, including Chandra, the CGRO and RXTE, will be ready, as are radio astronomers around the world. Since the physics of Cyg X-3 seem to resemble what happens in an Active Galactic Nucleus, it will be like a space trip to a quasar. |
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"Living with a Star": Will NASA's new big science program fly?It is the major new initiative in the science section of NASA's FY2001 budget proposal (see Update # 173 small items): a series of missions to explore space weather and to improve forecasts for solar-terrestrial effects that would cost $500 million through 2005 and $1.5 billion trough 2010 when most of the spacecraft would be in place to monitor the next solar maximum. The FY2001 request contains just a small down payment of that amount, $20m - but the program, the first major new NASA science initiative since the Origins program started in 1997, is already causing debate: Is it really NASA's mission to forecast the space weather or shouldn't other agencies do that? The network of spacecraft proposed consists of:
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To the Moon in 2008: India pushes ahead with mission plansA high level meeting of space and other scientists has endorsed the decision of the Indian Space Research Organization (ISRO) to launch a low-cost lunar mission, around 2008: Now the country's scientists have been invited to define the most promising science program for the spacecraft (see Updates # 133 small items and 169 story 3), with questions that none of the previous missions have answered. The spacecraft will be a lighther version of India's IRS remote sensing satellites and carry a camera with very high resolution: By studying the smallest craters on the Moon the distribution of asteroids in the 1 to 5 meter range could be investigated. Other possible tasks: observing levitating lunar dust raised by electrostatic forces and investigating volatiles, including water, and their transport mechanisms. The PSLV rocket should be able to send a 530 kg spacecraft on a lunar flyby or place a 350 kg satellite in orbit. (Space News of Feb. 28) |
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Origin of the Moon and tilt of the orbital plane: a theory of everything?Model calculations are closing in on all aspects of the origin of our Moon: Not only can its formation be explained by a giant impact that formed a disk of debris around the Earth from which the Moon coalesced - but gravitational effects from that disk can also explain why its orbital plane is not in the ecliptic. The inclination problem had been one of the last remaining obstacles for the impact hypothesis of moon formation: Now it has been explained in a more detailled scenario.To yield a lunar-sized moon, the giant impact must place about two lunar masses of material into an Earth-orbiting disk. Debris particles in the inner regions of such a disk are prevented from coalescing by tidal forces, which tend to pull objects apart. Instead, the moon rapidly coalesces at the outer edge of the debris disk, right at the Roche limit. The newly formed moon would have likely co-existed for some time with an inner disk of gas and debris left over from the impact - and its gravity would generate waves in the inner disk. The gravitational interaction of the moon with these waves would then, in turn, modify the lunar orbit. The waves are launched at certain locations in the disk where the motions of disk particles are in resonance with the motion of the moon. The waves generated at one such resonance - where the orbital period of the moon is approximately three times that of the disk particles - are called "bending waves," which corrugate the surface of the disk. The gravitational attraction between the moon and these rippled waves in the disk then acts to amplify the tilt of the moon's orbit, up to 15 degrees, before the disk dissipates. This theory thus explains the moon's anomalous orbital tilt as a natural consequence of its formation from a giant impact. (Ward & Canup, Nature of Feb. 17, p. 741-3) |
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The Lunar Prospector had a military mission, tooIt became famous for its - most likely - discovery of water on the Moon, but this feat of the neutron spectrometer aboard the Lunar Prospector was almost a by-product of its real mission, the Los Alamos National Labs that built it have now revealed. LANL, of course, is one of the U.S.' national nuclear laboratories - and even when it flies seemingly unrelated space experiments it is still involved in nuclear weapons matters, namely the deterrence of nuclear proliferation. Someone tempted to conduct a cladestine nuclear test should understand that the U.S. and its allies have very sophisticated monitoring capabilities, and the flight of the neutron spectrometer on the Lunar Prospector was a demonstration of that!The instrument looked at spallation neutrons generated when cosmic rays hit the lunar surface: They are moderated when they hit water-bearing material. From the measurements of neutrons from lunar orbit the presence and approximate amount of water could then be determined. "We can write that up [in prestigious journals] and talk about how great the scientific accomplishment is," says LANL's director for non-proliferation T. Hawkins: "If we can do that from an orbit around the Moon, the bad guys know we can probably see any neutrons generated by a [nuclear] device they test in space. And, of course, we can. We document those capabilities by doing unclassified research. You can't hide anymore..." (AW&ST of Feb. 21, p. 120-121) |
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M-5 failure, Astro-E loss traced to manufacturing flaw in nozzle coatingThe nozzle of Japan's M-5 rocket carrying the Astro-E X-ray satellite suffered a burn-through due to a failure of its carbon graphite fiber lining, the investigation has determined: Cameras mounted on the vehicle and launch telemetry show "a scattering of white foreign objects" appearing in the exhaust gases shortly after lift-off. At the same time the rocket started to shake, and a few seconds later a large plume, distinct from the exhaust gas, was observed, followed by a drop in thrust while the nozzle temperature rose. Again a few seconds later the rocket's attitude control system failed. This probably means that a carbon graphite heat-resistant coating inside the nozzle had ablated, exposing the nozzle to 3000 degrees C it could not withstand, with the heat also affecting the attitude control electronics. The failure of the composite material was most likely the result of sub-surface microbubbles that had formed during the curing process. (AW&ST of Feb. 21, p. 123-6) |
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RapidEye: 4 German satellites for agricultureIt's yet another system of Earth-observation satellites, but this time it's targeted towards a very specific group of customers: RapidEye Inc., incorporated in December 1998, is a new satellite based GEO-information service company that concentrates on customers in the agricultural and cartographic segments. On Feb. 2 Surrey Satellite Technology Ltd. (SSTL) was selected as the prime contractor and spacecraft platform supplier for the $100m RapidEye constellation of minisatellites. "RapidEye's clients will receive jointly developed geographic information products which will be integrated in the clients' work processes and offer significant cost advantages and new revenue potential," the German company is promising.The RapidEye Earth Observation system, to be launched in 2002 into 600-km polar orbits, will provide 6.5-meter resolution wide-swath multispectral imaging (up to 6 bands) with a daily revisit and is targeted primarily at agricultural applications. The company promises to have images available as well as tailored information (and not just raw data) when needed. Initially the program will focus on services for insurance companies, by assessing crops and their health as well as damages. The 380 kg RapidEye minisatellites will use the SSTL minisatellite platform whose capability has been demonstrated in orbit by the SSTL UoSAT-12 mission, launched in April 1999. (With AW&ST of Jan. 24, p. 67) |
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NASA report criticizes Boeing for ISS cost overrunsA report just released by NASA's Inspector General sharply criticized Boeing for not being forthcoming about the growing cost overruns on its International Space Station contract: Fla. Today, Space.com, AP, SpaceViews.Senate blocks any extra NASA ISS payments to Russia - unless President Clinton reports proof that Russia is working to stop weapons proliferation to Iran: AvNow. Station orbits quietly: Space Daily. "Non-traditional" markets the first significant commercial ISS users? A study commissioned by NASA has concluded that e.g. education, entertainment and advertising might start the commercial use of the station: SpaceViews. Mir motion picture plans move ahead, actor eager to fly: BBC, CSM. Terra satellite reaches final orbitThe mission's flight team at GSFC has completed the last of eight burns on the 23rd, to raise the Earth observer Terra to its final 705-kilometer polar orbit (see Update # 170 small items) - the $1.3 billion Terra now trails another Earth-observing satellite, Landsat 7, by 35 minutes, allowing the two to work in near unison: Space.com. |
Meteorite from Yukon fireball foundDebris from a fireball that exploded over Carcross, Yukon Territory, last month (see Update # 168-170 small items) has been found on a snow-covered lake along the Klondike Highway - a meteorite fragment weighing about 6 ounces was sent to the Johnson Space Center for analysis: Anchorage Daily News.Reflight of MPL in 2002 one of many optionsNASA is now considering sending a near duplicate of the Mars Polar Lander to the red planet in 2002 - that shot would replace a mission slated for launch a year earlier, but would use virtually the same spacecraft: Space.com.A privately financed Mars airplane for 2003? A company thinks it can be done: SpaceViews. Mars weather: It's stranger than you thought - and a far cry from the dry and dead world imagined by previous generations: Space.com. Summer on Mars' S hemisphere progresses: MSSS Release, PhotoJournal, CNN, Discovery.
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